Question

Why transpiration is the price which plants pays for photosynthesis

Answer 1

also due to water loss energy is released which is taken up by the plant the energy which energy is used up by the plant to absorb water from the soil water is also important of photosynthesis before transpiration is the price paid by plants for photosynthesis

Answer 2

Transportation is considered as price which plants pays for the photosynthesis ,as plants make O2,H2Oand ATP as product.
hence,H2O andO2 are released from the leafs.
The loss of water from the leafs of plants is called Transpiration.
the water from the leafs reaches atmosphere and again it makes rain, therefore
the plants get water again to continue the process of photosynthesis (as water is required for this process to be done).
Hope it'll be helpful to you dear.